EP-A-0 010 295 describes a process for preparing ethanol from synthesis gas, in which the reaction is carried out over a supported rhodium catalyst comprising, as cocatalyst, one or more of the elements zirconium, hafnium, lanthanum, platinum, chromium and mercury.
EP-A-0 079 132 relates to a process for preparing oxygenated hydrocarbons by catalytic reaction of synthesis gas over a supported catalyst comprising, as active components, rhodium, silver, zirconium and molybdenum and also, if desired, iron, manganese, rhenium, tungsten, ruthenium, chromium, thorium and potassium. The preferred support material is silicon dioxide.
JP 62/148437 and JP 62/148438 disclose the simultaneous production of acetic acid, acetaldehyde and ethanol from a synthesis gas reacted in the presence of a rhodium catalyst pretreated with sulfur-containing compounds. JP 61/178933 discloses producing oxygenates from a synthesis gas wherein the reaction is carried out in the presence of a rhodium catalyst provided with an accelerator metal such as scandium, iridium or an alkali earth metal. JP01/294643 discloses the production of oxygenated compounds such as acetic acid in which a synthesis gas is reacted in the presence of a rhodium catalyst on a silica substrate.
U.S. Pat. No. 6,346,555 and U.S. Pat. No. 6,500,781 disclose a catalyst and a process for preparing C2-oxygenates by reaction of CO and H2 over a rhodium-containing supported catalyst, in which the catalyst consists essentially of rhodium, zirconium, iridium, at least one metal selected from amongst copper, cobalt, nickel, manganese, iron, ruthenium and molybdenum, and at least one alkali metal or alkaline earth metal selected from amongst lithium, sodium, potassium, rubidium, magnesium and calcium, on an inert support